Behest p



(No Model.)

B. P. WARNER.

. TELEPHONE AND SIGNAL GIEOUIT. No. 284,102. Patented Aug. 28, 1888.

Q/ HLEJQSJJ' I 8 I Inwezninr UNIT D STATES PATENT Orrrcn.

ERNEST P. W VARNER, OF CHICAGO, ILLINOIS, ASSIGNOR TO THE WVESTERN ELECTRIC COMPANY, OF SAME PLACE.

TELEPHONE ANDISIGNAL CIRCUIT.

SPECIFICATION forming part of Letters Patent No. 284,102, dated August 28, 1883.

Application filed August 18, 1882.

ToaZZ whom it may concern:

Be it known that I, ERNnsr I. WARNER, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvementin Telephone and Signal Circuits, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawing, forming a part of IO this specification.

Prior to my invention it was common to divide a telephone-line in two branches and place the telephone in one bran oh and the bell in the other branch. Vhen the branch 0011- I 5 taining the telephone was connectedwith the switch, the other branch containing the signalbell was left open, and when the branch containing the bell was closed the branch contain ing the telephone was left open. In this manner the resistance of the coil of the electromagnet of one instrument was removed from the circuit when the other instrument was in use. Thus at a subscribers station, when the telephone was hung on. the switch, the circuit 2 5 was closed through the bell, while the branch containing the telephone was left open, and thus the resistance of the coils of its electroflmagnet was removed from the signal-circuit. The telephone, when thus disconnected, was not liable to injury from lightning. I11 case, however, the switch failed to make contact, both instruments were left open and became wholly inoperative. v

The object of my invention is to provide a 3 5 circuit for the telephone and signal instruments which may always be operative for signaling, whether the switch makes proper contact or not, and which is so arranged that the magnet of one instrument will be cut out by a shunt 40 of low resistance when the shunt of the electro-magnet of the other instrument is left open. Thus I have all of the advantages of the old open branch circuit as long as the contacts are properly made, and in case the switch fails to make proper contact, or makes no contact at all, still I have both instruments in circuit and operative, the only objection being the resistance of the electro-inagnet of one i'nstru ment remaining in the circuit when the other is in use.

contact-point c.

(No model.)

My invention is especially adapted for use in telephone call-boxes; but it maybe usedfor all analogous purposes where a telephone and signal instrument are to be switched out or in to a circuit alternatively.

The accompanying drawing is illustrative of my invention.

The telephone a and the signal-instru1nent b are placed in line in the main line. The circuit-changer c is permanently connected to the main line, between the telephone and signal-bell. Two contact-points, d and e, are provided in the main line near the circuit-changer.

The gravity telephoneswitch f is provided with the stud g, of insulating material. When the telephone is hung on the switch, as shown, the switch is brought to the position shown, and the stud g comes against the circuitchanger c, and the shunt is closed about the telephone, and a current sent through the sig- 7o nal-bell will not be weakened by the resistance of the coil of the electro-magnet of the telephone, or the secondary of induction coil. The local circuit of the transmitter and primary of the induction-coil is at the same time left open at point h. Thus the telephone and secondary of induction-coil are short-circuited by the circuit-changer and the local circuit broken at the switch as long as the telephone is not in use. On taking down the telephone for use the lever is lifted by the force of the spring 6 into contact with point h, thus closing the circuit of the local battery through the transmitter and primary of induction coil. The stud g is also carried away from the circuit-changer c, which is thus released, and by its own tension is brought into contact with the contactpoint (1 and disconnected from The bell is thus short-circuited when the telephone is in use. Suppose now, owing to some defect in the apparatus, as when the springs become weak, or when dust or rust gathers on the contact-points, both points d and 6 should at the same time be left open. In this case the telephone and bell will both be left directly in circuit, and either will be operative, the only objection being the resistance of one instrument remaining in the circuit when the other is in use.

The switching device as herein described is of novel construction, and, while especially adapted for usewith the circuits shown in my drawing, may also be used with the old open circuit, which was known prior to my invention.

For signaling I use the usual magneto-generator or battery-cell, which may be inserted in the line on either side of the bell.

1. The combination, in an electric circuit, of a telephone and a signal-bell with two contact-points, a circuit-changing piece connected to the main line between the bell and telephone, said circuit-changing piece being adaptedto close alternatively upon said contact-points,-

for the purpose specified.

2. The combination of a main electric circuit with a telephone signal-instrument, circuit-changing piece, and two contact-points, said circuit-changer being connected to the main circuit between the telephone and bell, and said contact-points being on the line side of thebell and telephone, respectively.

a 3. The combination of a telephone and bell placed in line in the main electric circuit between two contact-points, and a circuit-changer connected to the line between the bell and telephone, and adapted to make contact alternatively with said contact-points, whereby one instrumentthe telephone or bellmay be cut out by short circuit, when the other instrument is in use, without opening the main circuit.

4. The switch-lever, in combination with the circuit-changing piece, and connections, substantially as described, whereby the local circuit is closed through the primary of induction-coil and transmitter, and at the same time the resistance of the coils of the signal bell automatically removed fromthe talkingcircuit.

5. The combination, with a gravity telephoneswitch, of a circuit-changer adapted to be operated automatically thereby, said =circuit-' changer being connected permanently to the main line between the bell and telephone, and two contact-points, whereby the telephone and bell, respectively, may be shunted alternatively, substantially as and for the purpose specified. v

6. A movable switch provided with two contact-points, each connected permanently to the line and to one end of one of two loops containing a telephone and bell, respectively, and with a contact-piece or connector joined peradapted to make connection alternatively withthe two contact-points.

7. The combination of a pivoted switch ERNEST P. WARNER.

Witnesses:

P. A. STALEY, GEORGE P. BARTON.

55 manently to the other end of said loops, and I v 

